1. Field of the Invention:
The present invention relates to a method and an apparatus for image recognition to calculate the position and orientation of an object article and, more particularly, to a method and an apparatus for calculating the position and orientation of a whole object article inclusive of its partial shapes by comptuing the linear equations, centers of gravity and so forth of such partial shapes.
2. Description of the Prior Art:
In the part recognition technology developed heretofore, there is known an exemplary pattern recognition apparatus disclosed in Japanese Patent Laid-open No. 59 (1984)-154574 (Patent Application No. 58 (1983)-27518, U.S. Patent Ser. No. 582,555). According to this prior art, the pattern of an object article is recognized by first detecting the entire contour thereof and, after calculating its feature parameters such as center of gravity, principal axis and so forth, finding the degree of coincidence between the pattern of the object article and a selected dictionary pattern in a state where the two patterns are so set that the respective principal axes coincide with each other. However, in case the object article to be recognized is a printed circuit board or the like with electronic components mounted thereon and its image is extremely complicated or its external dimensions are large, there exist some disadvantages including that a distinct image of the whole object article cannot be obtained immediately or its shape cannot be obtained simultaneously. Consequently, fast calculation of feature parameters is not attainable with facility to substantially fail in proper recognition of the object article in practical operation.
Meanwhile, in Japanese Patent Laid-open No. 58 (1983)-62503, there is disclosed an invention which executes controlled positioning of a member on the basis of its area in a window set in a part of the image. However, since the positioning in the above example is performed merely using the area parameter, a precise position is not achievable.
Generally it has been customary in the prior art to place an object article under positive control so that its predetermined reference position and orientation are retained. When the position and orientation are properly recognized, the correlation between them and the reference ones is defined uniquely so that the object article can be controlled properly by correcting the reference position and orientation in accordance with such correlation. That is, proper control of the object article is sufficiently attainable by proper recognition of the current position and orientation.